"It's great for me being here. I have been able to face pretty much our (Yorkshire) first-team bowling attack in the nets, which is lucky. Hopefully I can get a few more hits in and be ready to get on the plane.
"Martyn Moxon (Yorkshire director of cricket) and Jason Gillespie (head coach) have been brilliant with me, organising some training."
Williamson will be Yorkshire's overseas player - replacing Australian Glenn Maxwell - and he's in line to feature in their final four County Championshp matches.
Yorkshire are unbeaten - winning six from nine matches - and are well placed to defend their title as they sit top of the ladder, fourteen points clear with two games in hand.
The Kiwi batsmen - ranked 6th in the ODI batting rankings - will also be available to feature in the later stages of the Royal London one day cup should Yorkshire qualify from their group.
The Black Caps tour of Zimbabwe and South Africa
August 2 - 1st ODI v Zimbabwe
August 4 - 2nd ODI v Zimbabwe
August 7 - 3rd ODI v Zimbabwe
August 9 - T20 International v Zimbabwe
August 14 -1st T20 International v South Africa
August 16 -2nd T20 International v South Africa
August 19 - 1st ODI v South Africa
August 23 - 2nd ODI v South Africa
August 26 - 3rd ODI v South Africa